Gas Law Calculators: Pressure, Volume and Temperature

Use these gas law calculators to solve for pressure, volume, temperature, and partial pressure in chemistry problems. Boyle’s Law and Charles' Law help you examine how a gas changes when one condition varies, while the Combined Gas Law handles changes in several conditions. Use the Ideal Gas Law to relate pressure, volume, temperature, and the amount of gas, or Dalton’s Law to work with gas mixtures.For concentration and dilution problems, try the C1V1 = C2V2 calculator. These tools are useful for students checking homework, teachers preparing examples, and anyone working through gas-law calculations.

Mean Free Path

Calculate the mean free path of gas molecules from temperature, pressure, and collision diameter. Enter the gas conditions in any common unit and get λ in nm, µm, mm, or m.

Gas Density

Calculate the density of any gas from its absolute pressure, temperature, and molar mass using the ideal gas law. Enter values in kPa, Pa, bar, atm, psi, or mmHg and °C, K, or °F — the result is shown in kg/m³, g/L, and lb/ft³.

Ideal Gas Law

Use pressure, temperature, volume, and moles of gas to solve the ideal gas law for one unknown. Enter the three known values in kPa, K, L, and mol.

Boyle’s Law

Use Boyle’s law to find a gas’s initial or final pressure or volume. Choose the unknown and enter the other three values, assuming constant temperature.

Molecular Speed of a Gas

Calculate the root-mean-square, mean, and most probable speeds of gas molecules from the temperature and molar mass, plus the average translational energy per mole, using kinetic theory formulas.

Dalton’s Law

Enter the moles of each gas, the temperature in kelvin, and the volume in liters to calculate mixture pressure. A unit-conversion error currently makes the displayed result 1,000 times too low.

Gay-Lussac's Law

Calculate how gas pressure changes with temperature in a sealed, rigid container using Gay-Lussac's law. Enter the initial pressure and temperature plus one final value to find the other.

Henry's Law

Calculate how much gas dissolves in a liquid at a given partial pressure using Henry's law. Enter the pressure and Henry's law constant to get the dissolved concentration, or solve for the pressure instead.

Charles' Law

Calculate the initial or final volume or temperature of a gas using Charles’ law. Select the value to find, then enter the other values at constant pressure.

Combined Gas Law

Find an unknown initial or final pressure, volume, or temperature using the combined gas law. Select the value to calculate, then enter the other five values.

Avogadro's Law

Calculate the missing volume or amount of gas using Avogadro's law. Enter the initial volume and amount, plus the new amount or new volume, and get the result with full steps.

Van der Waals Equation

Calculate the real-gas pressure from the Van der Waals equation. Enter the amount of gas, volume, temperature and the constants a and b to get the pressure, compressibility factor Z and the deviation from the ideal-gas law.

Graham's Law

Compare how fast two gases diffuse or effuse. Enter the molar masses of both gases (and a known rate if you have one) to get the rate ratio or the unknown rate from Graham's law.